Justice League was nothing short of fucking brilliant; it's easily the best non-joke material CN has aired, and I'd probably say the best non-joke animated material ever to come out of non-Japanese circles as well.
JLU has been more hit-and-miss, but I sure as hell still prefer it to no Justice League at all.
Whoever would have thought something so good would have come out of, for christ's sakes, DC Comics?
You, sir, are mad. Batman Beyond (at least the first two seasons) was stellar. And have a little faith. DC was also the source of Alan Moore's utterly brilliant run on Swamp Thing... which was almost singlehandedly responsible for the final elimination of the CCA.